﻿using System;
using System.IO;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Win32;

namespace SmartStore.Core.IO
{ 
    public static class MimeTypes
    {
		private static readonly char[] _pathSeparatorChars = new [] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar, Path.VolumeSeparatorChar };
		private static readonly Dictionary<string, string> _mimeMap;
		private static readonly Dictionary<string, string> _extMap;

		const string DefaultMimeType = "application/octet-stream";

		static MimeTypes()
		{
			// maps both ways,
			// extension -> mime type
			//   and
			// mime type -> extension
			//
			// any mime type on left side not pre-loaded on right side, are added automatically.
			// Some mime types can map to multiple extensions, so to get a deterministic mapping,
			// add those to the dictionary specifcially
			//
			// Some added based on http://www.iana.org/assignments/media-types/media-types.xhtml
			// which lists mime types, but not extensions
			//

			_mimeMap = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
			{
				#region Mime types > extension map

				{"application/fsharp-script", ".fsx"},
				{"application/msaccess", ".adp"},
				{"application/msword", ".doc"},
				{"application/octet-stream", ".bin"},
				{"application/onenote", ".one"},
				{"application/postscript", ".eps"},
				{"application/step", ".step"},
				{"application/vnd.ms-excel", ".xls"},
				{"application/vnd.ms-powerpoint", ".ppt"},
				{"application/vnd.ms-works", ".wks"},
				{"application/vnd.visio", ".vsd"},
				{"application/x-director", ".dir"},
				{"application/x-shockwave-flash", ".swf"},
				{"application/x-x509-ca-cert", ".cer"},
				{"application/x-zip-compressed", ".zip"},
				{"application/xhtml+xml", ".xhtml"},
				{"application/xml", ".xml"},  // anomoly, .xml -> text/xml, but application/xml -> many thingss, but all are xml, so safest is .xml
                {"audio/aac", ".AAC"},
				{"audio/aiff", ".aiff"},
				{"audio/basic", ".snd"},
				{"audio/mid", ".midi"},
				{"audio/wav", ".wav"},
				{"audio/x-m4a", ".m4a"},
				{"audio/x-mpegurl", ".m3u"},
				{"audio/x-pn-realaudio", ".ra"},
				{"audio/x-smd", ".smd"},
				{"image/bmp", ".bmp"},
				{"image/jpeg", ".jpg"},
				{"image/pict", ".pic"},
				{"image/png", ".png"}, //Defined in [RFC-2045], [RFC-2048]
                {"image/x-png", ".png"}, //See https://www.w3.org/TR/PNG/#A-Media-type :"It is recommended that implementations also recognize the media type "image/x-png"."
                {"image/tiff", ".tiff"},
				{"image/x-macpaint", ".mac"},
				{"image/x-quicktime", ".qti"},
				{"message/rfc822", ".eml"},
				{"text/html", ".html"},
				{"text/plain", ".txt"},
				{"text/scriptlet", ".wsc"},
				{"text/xml", ".xml"},
				{"video/3gpp", ".3gp"},
				{"video/3gpp2", ".3gp2"},
				{"video/mp4", ".mp4"},
				{"video/mpeg", ".mpg"},
				{"video/quicktime", ".mov"},
				{"video/vnd.dlna.mpeg-tts", ".m2t"},
				{"video/x-dv", ".dv"},
				{"video/x-la-asf", ".lsf"},
				{"video/x-ms-asf", ".asf"},
				{"x-world/x-vrml", ".xof"},

                #endregion
			};

			_extMap = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
			{
				#region Extension > mime type map
            
                {".323", "text/h323"},
				{".3g2", "video/3gpp2"},
				{".3gp", "video/3gpp"},
				{".3gp2", "video/3gpp2"},
				{".3gpp", "video/3gpp"},
				{".7z", "application/x-7z-compressed"},
				{".aa", "audio/audible"},
				{".AAC", "audio/aac"},
				{".aaf", "application/octet-stream"},
				{".aax", "audio/vnd.audible.aax"},
				{".ac3", "audio/ac3"},
				{".aca", "application/octet-stream"},
				{".accda", "application/msaccess.addin"},
				{".accdb", "application/msaccess"},
				{".accdc", "application/msaccess.cab"},
				{".accde", "application/msaccess"},
				{".accdr", "application/msaccess.runtime"},
				{".accdt", "application/msaccess"},
				{".accdw", "application/msaccess.webapplication"},
				{".accft", "application/msaccess.ftemplate"},
				{".acx", "application/internet-property-stream"},
				{".AddIn", "text/xml"},
				{".ade", "application/msaccess"},
				{".adobebridge", "application/x-bridge-url"},
				{".adp", "application/msaccess"},
				{".ADT", "audio/vnd.dlna.adts"},
				{".ADTS", "audio/aac"},
				{".afm", "application/octet-stream"},
				{".ai", "application/postscript"},
				{".aif", "audio/aiff"},
				{".aifc", "audio/aiff"},
				{".aiff", "audio/aiff"},
				{".air", "application/vnd.adobe.air-application-installer-package+zip"},
				{".amc", "application/mpeg"},
				{".anx", "application/annodex"},
				{".apk", "application/vnd.android.package-archive" },
				{".application", "application/x-ms-application"},
				{".art", "image/x-jg"},
				{".asa", "application/xml"},
				{".asax", "application/xml"},
				{".ascx", "application/xml"},
				{".asd", "application/octet-stream"},
				{".asf", "video/x-ms-asf"},
				{".ashx", "application/xml"},
				{".asi", "application/octet-stream"},
				{".asm", "text/plain"},
				{".asmx", "application/xml"},
				{".aspx", "application/xml"},
				{".asr", "video/x-ms-asf"},
				{".asx", "video/x-ms-asf"},
				{".atom", "application/atom+xml"},
				{".au", "audio/basic"},
				{".avi", "video/x-msvideo"},
				{".axa", "audio/annodex"},
				{".axs", "application/olescript"},
				{".axv", "video/annodex"},
				{".bas", "text/plain"},
				{".bcpio", "application/x-bcpio"},
				{".bin", "application/octet-stream"},
				{".bmp", "image/bmp"},
				{".c", "text/plain"},
				{".cab", "application/octet-stream"},
				{".caf", "audio/x-caf"},
				{".calx", "application/vnd.ms-office.calx"},
				{".cat", "application/vnd.ms-pki.seccat"},
				{".cc", "text/plain"},
				{".cd", "text/plain"},
				{".cdda", "audio/aiff"},
				{".cdf", "application/x-cdf"},
				{".cer", "application/x-x509-ca-cert"},
				{".cfg", "text/plain"},
				{".chm", "application/octet-stream"},
				{".class", "application/x-java-applet"},
				{".clp", "application/x-msclip"},
				{".cmd", "text/plain"},
				{".cmx", "image/x-cmx"},
				{".cnf", "text/plain"},
				{".cod", "image/cis-cod"},
				{".config", "application/xml"},
				{".contact", "text/x-ms-contact"},
				{".coverage", "application/xml"},
				{".cpio", "application/x-cpio"},
				{".cpp", "text/plain"},
				{".crd", "application/x-mscardfile"},
				{".crl", "application/pkix-crl"},
				{".crt", "application/x-x509-ca-cert"},
				{".cs", "text/plain"},
				{".csdproj", "text/plain"},
				{".csh", "application/x-csh"},
				{".csproj", "text/plain"},
				{".css", "text/css"},
				{".csv", "text/csv"},
				{".cur", "application/octet-stream"},
				{".cxx", "text/plain"},
				{".dat", "application/octet-stream"},
				{".datasource", "application/xml"},
				{".dbproj", "text/plain"},
				{".dcr", "application/x-director"},
				{".def", "text/plain"},
				{".deploy", "application/octet-stream"},
				{".der", "application/x-x509-ca-cert"},
				{".dgml", "application/xml"},
				{".dib", "image/bmp"},
				{".dif", "video/x-dv"},
				{".dir", "application/x-director"},
				{".disco", "text/xml"},
				{".divx", "video/divx"},
				{".dll", "application/x-msdownload"},
				{".dll.config", "text/xml"},
				{".dlm", "text/dlm"},
				{".doc", "application/msword"},
				{".docm", "application/vnd.ms-word.document.macroEnabled.12"},
				{".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
				{".dot", "application/msword"},
				{".dotm", "application/vnd.ms-word.template.macroEnabled.12"},
				{".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"},
				{".dsp", "application/octet-stream"},
				{".dsw", "text/plain"},
				{".dtd", "text/xml"},
				{".dtsConfig", "text/xml"},
				{".dv", "video/x-dv"},
				{".dvi", "application/x-dvi"},
				{".dwf", "drawing/x-dwf"},
				{".dwg", "application/acad"},
				{".dwp", "application/octet-stream"},
				{".dxf", "application/x-dxf" },
				{".dxr", "application/x-director"},
				{".eml", "message/rfc822"},
				{".emz", "application/octet-stream"},
				{".eot", "application/vnd.ms-fontobject"},
				{".eps", "application/postscript"},
				{".etl", "application/etl"},
				{".etx", "text/x-setext"},
				{".evy", "application/envoy"},
				{".exe", "application/octet-stream"},
				{".exe.config", "text/xml"},
				{".fdf", "application/vnd.fdf"},
				{".fif", "application/fractals"},
				{".filters", "application/xml"},
				{".fla", "application/octet-stream"},
				{".flac", "audio/flac"},
				{".flr", "x-world/x-vrml"},
				{".flv", "video/x-flv"},
				{".fsscript", "application/fsharp-script"},
				{".fsx", "application/fsharp-script"},
				{".generictest", "application/xml"},
				{".gif", "image/gif"},
				{".gpx", "application/gpx+xml"},
				{".group", "text/x-ms-group"},
				{".gsm", "audio/x-gsm"},
				{".gtar", "application/x-gtar"},
				{".gz", "application/x-gzip"},
				{".h", "text/plain"},
				{".hdf", "application/x-hdf"},
				{".hdml", "text/x-hdml"},
				{".hhc", "application/x-oleobject"},
				{".hhk", "application/octet-stream"},
				{".hhp", "application/octet-stream"},
				{".hlp", "application/winhlp"},
				{".hpp", "text/plain"},
				{".hqx", "application/mac-binhex40"},
				{".hta", "application/hta"},
				{".htc", "text/x-component"},
				{".htm", "text/html"},
				{".html", "text/html"},
				{".htt", "text/webviewhtml"},
				{".hxa", "application/xml"},
				{".hxc", "application/xml"},
				{".hxd", "application/octet-stream"},
				{".hxe", "application/xml"},
				{".hxf", "application/xml"},
				{".hxh", "application/octet-stream"},
				{".hxi", "application/octet-stream"},
				{".hxk", "application/xml"},
				{".hxq", "application/octet-stream"},
				{".hxr", "application/octet-stream"},
				{".hxs", "application/octet-stream"},
				{".hxt", "text/html"},
				{".hxv", "application/xml"},
				{".hxw", "application/octet-stream"},
				{".hxx", "text/plain"},
				{".i", "text/plain"},
				{".ico", "image/x-icon"},
				{".ics", "application/octet-stream"},
				{".idl", "text/plain"},
				{".ief", "image/ief"},
				{".iii", "application/x-iphone"},
				{".inc", "text/plain"},
				{".inf", "application/octet-stream"},
				{".ini", "text/plain"},
				{".inl", "text/plain"},
				{".ins", "application/x-internet-signup"},
				{".ipa", "application/x-itunes-ipa"},
				{".ipg", "application/x-itunes-ipg"},
				{".ipproj", "text/plain"},
				{".ipsw", "application/x-itunes-ipsw"},
				{".iqy", "text/x-ms-iqy"},
				{".isp", "application/x-internet-signup"},
				{".ite", "application/x-itunes-ite"},
				{".itlp", "application/x-itunes-itlp"},
				{".itms", "application/x-itunes-itms"},
				{".itpc", "application/x-itunes-itpc"},
				{".IVF", "video/x-ivf"},
				{".jar", "application/java-archive"},
				{".java", "application/octet-stream"},
				{".jck", "application/liquidmotion"},
				{".jcz", "application/liquidmotion"},
				{".jfif", "image/pjpeg"},
				{".jnlp", "application/x-java-jnlp-file"},
				{".jpb", "application/octet-stream"},
				{".jpe", "image/jpeg"},
				{".jpeg", "image/jpeg"},
				{".jpg", "image/jpeg"},
				{".js", "application/javascript"},
				{".json", "application/json"},
				{".jsx", "text/jscript"},
				{".jsxbin", "text/plain"},
				{".latex", "application/x-latex"},
				{".library-ms", "application/windows-library+xml"},
				{".lit", "application/x-ms-reader"},
				{".loadtest", "application/xml"},
				{".lpk", "application/octet-stream"},
				{".lsf", "video/x-la-asf"},
				{".lst", "text/plain"},
				{".lsx", "video/x-la-asf"},
				{".lzh", "application/octet-stream"},
				{".m13", "application/x-msmediaview"},
				{".m14", "application/x-msmediaview"},
				{".m1v", "video/mpeg"},
				{".m2t", "video/vnd.dlna.mpeg-tts"},
				{".m2ts", "video/vnd.dlna.mpeg-tts"},
				{".m2v", "video/mpeg"},
				{".m3u", "audio/x-mpegurl"},
				{".m3u8", "audio/x-mpegurl"},
				{".m4a", "audio/m4a"},
				{".m4b", "audio/m4b"},
				{".m4p", "audio/m4p"},
				{".m4r", "audio/x-m4r"},
				{".m4v", "video/x-m4v"},
				{".mac", "image/x-macpaint"},
				{".mak", "text/plain"},
				{".man", "application/x-troff-man"},
				{".manifest", "application/x-ms-manifest"},
				{".map", "text/plain"},
				{".master", "application/xml"},
				{".mbox", "application/mbox"},
				{".mda", "application/msaccess"},
				{".mdb", "application/x-msaccess"},
				{".mde", "application/msaccess"},
				{".mdp", "application/octet-stream"},
				{".me", "application/x-troff-me"},
				{".mfp", "application/x-shockwave-flash"},
				{".mht", "message/rfc822"},
				{".mhtml", "message/rfc822"},
				{".mid", "audio/mid"},
				{".midi", "audio/mid"},
				{".mix", "application/octet-stream"},
				{".mk", "text/plain"},
				{".mk3d", "video/x-matroska-3d"},
				{".mka", "audio/x-matroska"},
				{".mkv", "video/x-matroska"},
				{".mmf", "application/x-smaf"},
				{".mno", "text/xml"},
				{".mny", "application/x-msmoney"},
				{".mod", "video/mpeg"},
				{".mov", "video/quicktime"},
				{".movie", "video/x-sgi-movie"},
				{".mp2", "video/mpeg"},
				{".mp2v", "video/mpeg"},
				{".mp3", "audio/mpeg"},
				{".mp4", "video/mp4"},
				{".mp4v", "video/mp4"},
				{".mpa", "video/mpeg"},
				{".mpe", "video/mpeg"},
				{".mpeg", "video/mpeg"},
				{".mpf", "application/vnd.ms-mediapackage"},
				{".mpg", "video/mpeg"},
				{".mpp", "application/vnd.ms-project"},
				{".mpv2", "video/mpeg"},
				{".mqv", "video/quicktime"},
				{".ms", "application/x-troff-ms"},
				{".msg", "application/vnd.ms-outlook"},
				{".msi", "application/octet-stream"},
				{".mso", "application/octet-stream"},
				{".mts", "video/vnd.dlna.mpeg-tts"},
				{".mtx", "application/xml"},
				{".mvb", "application/x-msmediaview"},
				{".mvc", "application/x-miva-compiled"},
				{".mxp", "application/x-mmxp"},
				{".nc", "application/x-netcdf"},
				{".nsc", "video/x-ms-asf"},
				{".nws", "message/rfc822"},
				{".ocx", "application/octet-stream"},
				{".oda", "application/oda"},
				{".odb", "application/vnd.oasis.opendocument.database"},
				{".odc", "application/vnd.oasis.opendocument.chart"},
				{".odf", "application/vnd.oasis.opendocument.formula"},
				{".odg", "application/vnd.oasis.opendocument.graphics"},
				{".odh", "text/plain"},
				{".odi", "application/vnd.oasis.opendocument.image"},
				{".odl", "text/plain"},
				{".odm", "application/vnd.oasis.opendocument.text-master"},
				{".odp", "application/vnd.oasis.opendocument.presentation"},
				{".ods", "application/vnd.oasis.opendocument.spreadsheet"},
				{".odt", "application/vnd.oasis.opendocument.text"},
				{".oga", "audio/ogg"},
				{".ogg", "audio/ogg"},
				{".ogv", "video/ogg"},
				{".ogx", "application/ogg"},
				{".one", "application/onenote"},
				{".onea", "application/onenote"},
				{".onepkg", "application/onenote"},
				{".onetmp", "application/onenote"},
				{".onetoc", "application/onenote"},
				{".onetoc2", "application/onenote"},
				{".opus", "audio/ogg"},
				{".orderedtest", "application/xml"},
				{".osdx", "application/opensearchdescription+xml"},
				{".otf", "application/font-sfnt"},
				{".otg", "application/vnd.oasis.opendocument.graphics-template"},
				{".oth", "application/vnd.oasis.opendocument.text-web"},
				{".otp", "application/vnd.oasis.opendocument.presentation-template"},
				{".ots", "application/vnd.oasis.opendocument.spreadsheet-template"},
				{".ott", "application/vnd.oasis.opendocument.text-template"},
				{".oxt", "application/vnd.openofficeorg.extension"},
				{".p10", "application/pkcs10"},
				{".p12", "application/x-pkcs12"},
				{".p7b", "application/x-pkcs7-certificates"},
				{".p7c", "application/pkcs7-mime"},
				{".p7m", "application/pkcs7-mime"},
				{".p7r", "application/x-pkcs7-certreqresp"},
				{".p7s", "application/pkcs7-signature"},
				{".pbm", "image/x-portable-bitmap"},
				{".pcast", "application/x-podcast"},
				{".pct", "image/pict"},
				{".pcx", "application/octet-stream"},
				{".pcz", "application/octet-stream"},
				{".pdf", "application/pdf"},
				{".pfb", "application/octet-stream"},
				{".pfm", "application/octet-stream"},
				{".pfx", "application/x-pkcs12"},
				{".pgm", "image/x-portable-graymap"},
				{".pic", "image/pict"},
				{".pict", "image/pict"},
				{".pjp", "image/jpeg"},
				{".pkgdef", "text/plain"},
				{".pkgundef", "text/plain"},
				{".pko", "application/vnd.ms-pki.pko"},
				{".pls", "audio/scpls"},
				{".pma", "application/x-perfmon"},
				{".pmc", "application/x-perfmon"},
				{".pml", "application/x-perfmon"},
				{".pmr", "application/x-perfmon"},
				{".pmw", "application/x-perfmon"},
				{".png", "image/png"},
				{".pnm", "image/x-portable-anymap"},
				{".pnt", "image/x-macpaint"},
				{".pntg", "image/x-macpaint"},
				{".pnz", "image/png"},
				{".pot", "application/vnd.ms-powerpoint"},
				{".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12"},
				{".potx", "application/vnd.openxmlformats-officedocument.presentationml.template"},
				{".ppa", "application/vnd.ms-powerpoint"},
				{".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12"},
				{".ppm", "image/x-portable-pixmap"},
				{".pps", "application/vnd.ms-powerpoint"},
				{".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12"},
				{".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow"},
				{".ppt", "application/vnd.ms-powerpoint"},
				{".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12"},
				{".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
				{".prf", "application/pics-rules"},
				{".prm", "application/octet-stream"},
				{".prx", "application/octet-stream"},
				{".ps", "application/postscript"},
				{".psc1", "application/PowerShell"},
				{".psd", "application/octet-stream"},
				{".psess", "application/xml"},
				{".psm", "application/octet-stream"},
				{".psp", "application/octet-stream"},
				{".pst", "application/vnd.ms-outlook"},
				{".pub", "application/x-mspublisher"},
				{".pwz", "application/vnd.ms-powerpoint"},
				{".qht", "text/x-html-insertion"},
				{".qhtm", "text/x-html-insertion"},
				{".qt", "video/quicktime"},
				{".qti", "image/x-quicktime"},
				{".qtif", "image/x-quicktime"},
				{".qtl", "application/x-quicktimeplayer"},
				{".qxd", "application/octet-stream"},
				{".ra", "audio/x-pn-realaudio"},
				{".ram", "audio/x-pn-realaudio"},
				{".rar", "application/x-rar-compressed"},
				{".ras", "image/x-cmu-raster"},
				{".rat", "application/rat-file"},
				{".rc", "text/plain"},
				{".rc2", "text/plain"},
				{".rct", "text/plain"},
				{".rdlc", "application/xml"},
				{".reg", "text/plain"},
				{".resx", "application/xml"},
				{".rf", "image/vnd.rn-realflash"},
				{".rgb", "image/x-rgb"},
				{".rgs", "text/plain"},
				{".rm", "application/vnd.rn-realmedia"},
				{".rmi", "audio/mid"},
				{".rmp", "application/vnd.rn-rn_music_package"},
				{".roff", "application/x-troff"},
				{".rpm", "audio/x-pn-realaudio-plugin"},
				{".rqy", "text/x-ms-rqy"},
				{".rtf", "application/rtf"},
				{".rtx", "text/richtext"},
				{".rvt", "application/octet-stream" },
				{".ruleset", "application/xml"},
				{".s", "text/plain"},
				{".safariextz", "application/x-safari-safariextz"},
				{".scd", "application/x-msschedule"},
				{".scr", "text/plain"},
				{".sct", "text/scriptlet"},
				{".sd2", "audio/x-sd2"},
				{".sdp", "application/sdp"},
				{".sea", "application/octet-stream"},
				{".searchConnector-ms", "application/windows-search-connector+xml"},
				{".setpay", "application/set-payment-initiation"},
				{".setreg", "application/set-registration-initiation"},
				{".settings", "application/xml"},
				{".sgimb", "application/x-sgimb"},
				{".sgml", "text/sgml"},
				{".sh", "application/x-sh"},
				{".shar", "application/x-shar"},
				{".shtml", "text/html"},
				{".sit", "application/x-stuffit"},
				{".sitemap", "application/xml"},
				{".skin", "application/xml"},
				{".skp", "application/x-koan" },
				{".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12"},
				{".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide"},
				{".slk", "application/vnd.ms-excel"},
				{".sln", "text/plain"},
				{".slupkg-ms", "application/x-ms-license"},
				{".smd", "audio/x-smd"},
				{".smi", "application/octet-stream"},
				{".smx", "audio/x-smd"},
				{".smz", "audio/x-smd"},
				{".snd", "audio/basic"},
				{".snippet", "application/xml"},
				{".snp", "application/octet-stream"},
				{".sol", "text/plain"},
				{".sor", "text/plain"},
				{".spc", "application/x-pkcs7-certificates"},
				{".spl", "application/futuresplash"},
				{".spx", "audio/ogg"},
				{".src", "application/x-wais-source"},
				{".srf", "text/plain"},
				{".SSISDeploymentManifest", "text/xml"},
				{".ssm", "application/streamingmedia"},
				{".sst", "application/vnd.ms-pki.certstore"},
				{".stl", "application/vnd.ms-pki.stl"},
				{".sv4cpio", "application/x-sv4cpio"},
				{".sv4crc", "application/x-sv4crc"},
				{".svc", "application/xml"},
				{".svg", "image/svg+xml"},
				{".swf", "application/x-shockwave-flash"},
				{".step", "application/step"},
				{".stp", "application/step"},
				{".t", "application/x-troff"},
				{".tar", "application/x-tar"},
				{".tcl", "application/x-tcl"},
				{".testrunconfig", "application/xml"},
				{".testsettings", "application/xml"},
				{".tex", "application/x-tex"},
				{".texi", "application/x-texinfo"},
				{".texinfo", "application/x-texinfo"},
				{".tgz", "application/x-compressed"},
				{".thmx", "application/vnd.ms-officetheme"},
				{".thn", "application/octet-stream"},
				{".tif", "image/tiff"},
				{".tiff", "image/tiff"},
				{".tlh", "text/plain"},
				{".tli", "text/plain"},
				{".toc", "application/octet-stream"},
				{".tr", "application/x-troff"},
				{".trm", "application/x-msterminal"},
				{".trx", "application/xml"},
				{".ts", "video/vnd.dlna.mpeg-tts"},
				{".tsv", "text/tab-separated-values"},
				{".ttf", "application/font-sfnt"},
				{".tts", "video/vnd.dlna.mpeg-tts"},
				{".txt", "text/plain"},
				{".u32", "application/octet-stream"},
				{".uls", "text/iuls"},
				{".user", "text/plain"},
				{".ustar", "application/x-ustar"},
				{".vb", "text/plain"},
				{".vbdproj", "text/plain"},
				{".vbk", "video/mpeg"},
				{".vbproj", "text/plain"},
				{".vbs", "text/vbscript"},
				{".vcf", "text/x-vcard"},
				{".vcproj", "application/xml"},
				{".vcs", "text/plain"},
				{".vcxproj", "application/xml"},
				{".vddproj", "text/plain"},
				{".vdp", "text/plain"},
				{".vdproj", "text/plain"},
				{".vdx", "application/vnd.ms-visio.viewer"},
				{".vml", "text/xml"},
				{".vscontent", "application/xml"},
				{".vsct", "text/xml"},
				{".vsd", "application/vnd.visio"},
				{".vsi", "application/ms-vsi"},
				{".vsix", "application/vsix"},
				{".vsixlangpack", "text/xml"},
				{".vsixmanifest", "text/xml"},
				{".vsmdi", "application/xml"},
				{".vspscc", "text/plain"},
				{".vss", "application/vnd.visio"},
				{".vsscc", "text/plain"},
				{".vssettings", "text/xml"},
				{".vssscc", "text/plain"},
				{".vst", "application/vnd.visio"},
				{".vstemplate", "text/xml"},
				{".vsto", "application/x-ms-vsto"},
				{".vsw", "application/vnd.visio"},
				{".vsx", "application/vnd.visio"},
				{".vtt", "text/vtt"},
				{".vtx", "application/vnd.visio"},
				{".wasm", "application/wasm"},
				{".wav", "audio/wav"},
				{".wave", "audio/wav"},
				{".wax", "audio/x-ms-wax"},
				{".wbk", "application/msword"},
				{".wbmp", "image/vnd.wap.wbmp"},
				{".wcm", "application/vnd.ms-works"},
				{".wdb", "application/vnd.ms-works"},
				{".wdp", "image/vnd.ms-photo"},
				{".webarchive", "application/x-safari-webarchive"},
				{".webm", "video/webm"},
				{".webp", "image/webp"}, /* https://en.wikipedia.org/wiki/WebP */
                {".webtest", "application/xml"},
				{".wiq", "application/xml"},
				{".wiz", "application/msword"},
				{".wks", "application/vnd.ms-works"},
				{".WLMP", "application/wlmoviemaker"},
				{".wlpginstall", "application/x-wlpg-detect"},
				{".wlpginstall3", "application/x-wlpg3-detect"},
				{".wm", "video/x-ms-wm"},
				{".wma", "audio/x-ms-wma"},
				{".wmd", "application/x-ms-wmd"},
				{".wmf", "application/x-msmetafile"},
				{".wml", "text/vnd.wap.wml"},
				{".wmlc", "application/vnd.wap.wmlc"},
				{".wmls", "text/vnd.wap.wmlscript"},
				{".wmlsc", "application/vnd.wap.wmlscriptc"},
				{".wmp", "video/x-ms-wmp"},
				{".wmv", "video/x-ms-wmv"},
				{".wmx", "video/x-ms-wmx"},
				{".wmz", "application/x-ms-wmz"},
				{".woff", "application/font-woff"},
				{".woff2", "application/font-woff2"},
				{".wpl", "application/vnd.ms-wpl"},
				{".wps", "application/vnd.ms-works"},
				{".wri", "application/x-mswrite"},
				{".wrl", "x-world/x-vrml"},
				{".wrz", "x-world/x-vrml"},
				{".wsc", "text/scriptlet"},
				{".wsdl", "text/xml"},
				{".wvx", "video/x-ms-wvx"},
				{".x", "application/directx"},
				{".xaf", "x-world/x-vrml"},
				{".xaml", "application/xaml+xml"},
				{".xap", "application/x-silverlight-app"},
				{".xbap", "application/x-ms-xbap"},
				{".xbm", "image/x-xbitmap"},
				{".xdr", "text/plain"},
				{".xht", "application/xhtml+xml"},
				{".xhtml", "application/xhtml+xml"},
				{".xla", "application/vnd.ms-excel"},
				{".xlam", "application/vnd.ms-excel.addin.macroEnabled.12"},
				{".xlc", "application/vnd.ms-excel"},
				{".xld", "application/vnd.ms-excel"},
				{".xlk", "application/vnd.ms-excel"},
				{".xll", "application/vnd.ms-excel"},
				{".xlm", "application/vnd.ms-excel"},
				{".xls", "application/vnd.ms-excel"},
				{".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12"},
				{".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12"},
				{".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
				{".xlt", "application/vnd.ms-excel"},
				{".xltm", "application/vnd.ms-excel.template.macroEnabled.12"},
				{".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template"},
				{".xlw", "application/vnd.ms-excel"},
				{".xml", "text/xml"},
				{".xmp", "application/octet-stream" },
				{".xmta", "application/xml"},
				{".xof", "x-world/x-vrml"},
				{".XOML", "text/plain"},
				{".xpm", "image/x-xpixmap"},
				{".xps", "application/vnd.ms-xpsdocument"},
				{".xrm-ms", "text/xml"},
				{".xsc", "application/xml"},
				{".xsd", "text/xml"},
				{".xsf", "text/xml"},
				{".xsl", "text/xml"},
				{".xslt", "text/xml"},
				{".xsn", "application/octet-stream"},
				{".xss", "application/xml"},
				{".xspf", "application/xspf+xml"},
				{".xtp", "application/octet-stream"},
				{".xwd", "image/x-xwindowdump"},
				{".z", "application/x-compress"},
				{".zip", "application/zip"},

                #endregion
			};

			// Shuffle entries
			ShuffleMap(_mimeMap, _extMap);
			ShuffleMap(_extMap, _mimeMap);

			// Complement maps with entries from registry
			try
			{
				using (var key = Registry.ClassesRoot.OpenSubKey(@"MIME\Database\Content Type", false))
				{
					if (key != null)
					{
						var subKeyNames = key.GetSubKeyNames();
						foreach (var contentType in subKeyNames)
						{
							if (!_mimeMap.ContainsKey(contentType))
							{
								// Our map does not contain this entry. We gonna add it.
								using (var subKey = key.OpenSubKey(contentType, false))
								{
									object extension = subKey.GetValue("Extension", null);
									if (extension != null)
									{
										// MimeType > Extension
										var ext = extension.ToString();
										_mimeMap.Add(contentType, ext);

										// Vice versa, Extension > MimeType
										if (!_extMap.ContainsKey(ext))
										{
											_extMap.Add(ext, contentType);
										}
									}
								}
							}
						}
					}
				}
			}
			catch { }
		}

		public static string MapNameToMimeType(string fileNameOrExtension)
        {
			var fileName = GetFileName(fileNameOrExtension);

			for (int i = 0; i < fileName.Length; i++)
			{
				if ((fileName[i] == '.') && _extMap.TryGetValue(fileName.Substring(i), out var str))
				{
					return str;
				}
			}


			return DefaultMimeType;
        }

        /// <summary>
        /// Returns the (dotless) extension for a mime type
        /// </summary>
        /// <param name="mimeType">The mime type</param>
        /// <returns>The corresponding file extension (without dot)</returns>
        [SuppressMessage("ReSharper", "RedundantAssignment")]
        public static string MapMimeTypeToExtension(string mimeType)
        {
            if (mimeType.IsEmpty())
                return null;

			if (_mimeMap.TryGetValue(mimeType, out var extension))
			{
				return extension.TrimStart('.');
			}

			return null;
        }

		private static void ShuffleMap(Dictionary<string, string> source, Dictionary<string, string> target)
		{
			foreach (var kvp in source)
			{
				if (!target.ContainsKey(kvp.Value))
				{
					target.Add(kvp.Value, kvp.Key);
				}
			}
		}

		private static string GetFileName(string path)
		{
			var startIndex = path.LastIndexOfAny(_pathSeparatorChars);
			if (startIndex < 0)
			{
				return path;
			}

			return path.Substring(startIndex);
		}
	}
}
